Mechanisms of plant growth promotion by PGPB
PGPB mediated plant growth promotion occurs by the alteration of the whole microbial community in rhizosphere niche through the production of various substances (Table 1).Generally, PGPB promote plant growth directly by either facilitating resource acquisition (nitrogen, phosphorus and essential minerals) or modulating plant hormone levels, or indirectly by decreasing the inhibitory effects of various pathogens on plant growth and development in the forms of
biocontrol agents (Glick, 2012; Ahemad and Kibret, 2014).